Electroless plating is widely used as an industrial technique which can change non-conductive base material surfaces such as those of plastics, ceramics, paper, glass, and fibers into conductive surfaces. Especially when a surface of non-conductive base material is to be electrolytically plated, the non-conductive base material is electrolessly plated as a pretreatment for the electrolytic plating.
However, it is difficult to form electroless plate directly on a surface of non-conductive base material. This is because it is difficult to adhere a catalyst layer as a pretreatment for electroless plating to a base material surface, since the non-conductive base material has a smooth surface.
Therefore, surface of the non-conductive base material is conventionally roughened by a mechanical treatment or chemical treatment to enable adhesion of a catalyst to the base material surface. However, if surface of the base material is roughened, the material as a whole becomes opaque, and therefore there arises a problem that the material becomes unsuitable for use requiring transparency.
As means for solving this problem, there has been proposed a means for forming a gelatinous thin membrane containing a water-soluble polymer (catalyst adhering layer) on a non-conductive base material (Patent document 1).    Patent document 1: Japanese Patent Unexamined Publication (KOKAI) No. 2002-220677 (claims)